Hi,
>> if someone posts shared calendar item it doesn't show up for others
When users made changes to shared calendar, they can log on their web mail to see if same changes have been synced to the web mail.
To avoid sync issue under cached Exchange mode, we can set to not cache shared folders. So, we can use email account under cached Exchange
mode but using shared calendar under Online mode. To do this, please check steps below:
1. Go to File > Account Settings > Account Settings.
2. Select your Exchange account and click Change.
3. Click More Settings.
4. Under Advanced tab, unselect "Download shared folders".

5. Click Apply and then OK.
6. Restart Outlook.
Hope the information is helpful to you.
Regards,
Perry
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